136304-78-4Relevant articles and documents
New practical synthesis of the key intermediate of candesartan
Porcs-Makkay, Marta,Mezei, Tibor,Simig, Gyula
, p. 490 - 493 (2007)
The development of a new, practical synthesis of methyl 3-amino-N-(2′-cyanobiphenyl-4-yl)methyl]anthranilate, key intermediate of candesartan, is described, starting from methyl anthranilate. The features of our approach are as follows: (i) introduction of the 3-nitro group by acid catalysed rearrangement of the corresponding methyl N-nitroanthranilate; (ii) introduction of a (2′-cyanobiphenyl-4-yl)methyl side chain by N-alkylation of the appropriate N-nitroanthranilic acid derivative. In the most efficient procedure methyl N,3-dinitroanthranilate was N-alkylated with 4′-bromomethyl-biphenyl-2-nitrile. Catalytic reduction of the aromatic nitro group was accompanied with the removal of the N-nitro function to afford the required key intermediate in good yield.
PROCESS FOR PREPARATION OF CANDESART AN CILEXETIL SUBSTANTIALLY FREE OF DES-CANDESARTAN CILEXETIL IMPURITY
-
Page/Page column 6, (2011/12/04)
The present invention provides a process for preparation of candeartan cilexetil substantially free of 2,3-dihydro-2-oxo-3-[[2'-(2H-tetrazol-5-yl)[l,l-biphenyl]-4- yl]methyl]-l-[[(cyclohexyloxy)carbonyl]oxy]ethylester-lH-benzimidazole-7- carboxylate (des-candesartan cilexetil) impurity.
CRYSTAL AND PROCESS FOR PRODUCING THE SAME
-
Page 18, (2010/02/06)
A process for producing crystals of 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H-benzimdazole-7-carboxylic acid (compound (I)), characterized by dissolving or suspending the compound (I) or a salt thereof in a solvent comprising an aprotic polar solvent and crystallizing it. By the process, the contaminants which are contained in the compound (I) or its salt and are difficult to remove, such as tin compounds, analogues of the compound (I), and a residual organic solvent, can be easily removed. Crystals of the compound (I) can be efficiently and easily mass-produced in high yield on an industrial scale.